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<br /> <br />~ b <br />\`~ <br />a. we must determine if these requirements apply to the final tailings bsfore <br />reclamation or whether they apply to the tailings-pond itself. If the <br />former, then it is possible; if the latter then it cannot: occur because: <br />_ _.__.~ <br />b. Typically in the gold-processing industry tailings contiain 100-200 ppm <br />free-cyanide plus same WAD. WAD varies with the metal cohtent of the ore <br />but free-cyanide is inevitable because it is this speci~s that extracts <br />tha gold. <br />Mo matter how large the fallings-pond, nor how long the d~e11-time in the <br />pond, there is no known process that can, in a contt uous operation, <br />reduce free-CN to less than 1 ppm without introducing di a consequences. <br />The permit condition outlined above asks BMG to have a fr e-cyanide level <br />of 0.6 ppm max. (4.4-3.8). Further, 4.4 ppm refers t Total. It is <br />impossible to generate 100-200 ppm free-cyanide and co vert it to 4.4 <br />total, when total is already 100-200 ppm. <br />This logical inexactitude can easily be rectified by ',re-defining the <br />standard, for example: <br />Total = x ppm <br />WAD = y ppm <br />Free = z ppm <br />But again, only WAD and Free shoultl concern us since only these generate <br />toxic end-products. Perhaps we should "forget" total. <br />3. Sgfe Cyanide Levels <br />Chemically, nobody haS yet defined a "safe" level when applied t gold-processing <br />operations. The nearest definition comes from the U.S. Fish and Wildlife Service <br />1n their publication "85 (1.23)", which states that Free cyanid should be below <br />50 ppm. We all know that MAD, although less toxic than Free, is still dangerous, <br />but no WAD taxieity Levels are yet in print. <br />All goltl-processors know the level of toxicity that is 171ega1 -I it is that which <br />kills birds - xhatever it is at each s eci is site!! <br />4. BFT Suaaestions to BMG and tFje State of Colorado <br />We believe that the following should be true for BMG, San Luis, kith the approval <br />of the State of Colorado. <br />a. No wildlife shall die as a result of the existence of Sin Luis (BMG). <br />b. Free cyanide shall be less than 30 ppm in the fallings ponds (available to <br />waterfowl). <br />c. True WAD cyanide shall be less than 40 ppm in the ta111n~s ponds (approx. <br />equivalent to 20 Free). <br />~1~9'd ~JdOS:TO ~6, LO 21dH <br />